Recessing tool



May l0, 1966 H. F. ARMSTRONG RECESS ING TOOL 2 Sheets-Sheet l Filed Jan. 5, 1965 MaY 10, 1966 H. F. ARMSTRONG 3,250,155

RECESSING TOOL v Filed Jan. 5, 1965 2 Sheets-Sheet 2 25 0 rifa United States Patent O 3,250,155 RECESSING TOOL Harold F. Armstrong, Milford, N.H., assignor to The O.K. Tool Company, Inc., Milford, N.H., a corporation of New Hampshire Filed Jan. 5, 1965, Ser. No. 423,553 4 Claims. (Cl. 77--58) This invention relates to a tool for cutting one or more grooves in a Acircular bore, commonly called a recessing tool. Heretofore such tools have had various disadvantages. One disadvantage consists in that the cutting bits have been expensive. Another disadvantage consists in that the cutting bits tend to vibrate.

Objects of the present invention are to overcome the aforesaid difficulties and to provide a tool in which the bits are small and inexpensive, and in which vibration of the bits is prevented. l

According to this invention the tool comprises a tubular rotor having its forward end small enough to extend into the aforesaid bore, a shaft journaled in the rotor with its axis offset from the axis of the rotor, an annular slot in the aforesaid end of the rotor, a bit mounted on the shaft to project through the slot when the shaft is turned relatively to the rotor, means to turn the shaft as aforesaid while the rotor is rotating, and a bearing for the shaft in the aforesaid end beyond said slot. Preferably, the tool has means accessible through the aforesaid slot for detachably mounting a bit on the shaft, a sleeve slidable between the rotor and shaft with a spiral tooth on the sleeve fitting in a spiral groove in the shaft, and a bearing for the rotor beyond the aforesaid slot.

For the purpose of illustration a typical embodiment of the invention is shown in the accompanying drawings in which FIG. 1 is a side view with the parts in retracted position;

FIG. 2 is a longitudinal section with the tool advanced into a bore;

FIG. 3 is a similar section with the cutting teeth projected through the aforesaid slots into contact with the bore;

FIG. 4 is a section on line 4-4 of FIG. 3;

FIG. 5 is a section on line 5 5 of FIG. 4;

FIG. 6 is a front end view of the aforesaid sleeve;

FIG. '7 is a section on line 7-7 of FIG. 6;

FIG. 8 is .a side view of an actuator for the aforesaid sleeve; and

FIG. 9 is a frontend view of the actuator.

The particular embodiment of the invention chosen for the purpose of illustration comprises an actuator 1 rotated by a suitable source of power. Surrounding the lower end of the actuator is a tubular rotor 2 with a sealing ring 3 between the two parts. Threaded on the upper end of the rotor is a collar 4 carrying a thrust bearing 6 adapted to seat against a stationary bearing 7. Threaded on the actuator 1 is a collar 8 adapted to seat against the collar 4. slot 9 to receive a pin 10 in the rotor 2 to permit endwise movement of the actuator in the rotor while preventing relative rotation. Fast in the lower end of the actuator is a sleeve 11 having on its outer periphery .a flange 12 provided with recesses 13 to receive teeth 14 on the lower end of the actuator 1 (FIGS. 6 and 7). On its inner periphery are spiral teeth 15. A shaft 16 has its upper end journaled in' the sleeve 11 and its lower end 17 journaled in an extension 18 of the rotor 2 with an intermediate bearing 19 in the lower end of the rotor. In its upper end the shaft has spiral grooves 21 to receive the spiral teeth 15. Between the rotor 2 and shaft 16 is a spring 22 yieldingly to urge the rotor downwardly relaice through the slot 25, the bit being mounted on the shaft by means of screws 28 and pin 29. As shown in FIGS. 2 and 3, and more clearly in FIGS. 4, 6 and 9, the axis 31 of the shaft 16 is offset from the axis 32 of the rotor 2 so that the cutting teeth 27 are gradually projected through the slot when the shaft is rotated counterclockwise (FIG. 4) to carry the bit from the broken-line position to the fuel-line position.

As shown in FIGS. l to 3 an additional bearing O may be provided for the lower end of the rotor but for most Work this is unnecessary.

In operation the tool is moved downwardly from the position shown in FIG. l to the position shown in FIG. 2 to bring bit 26 inside the bore B of the stocks to be recessed. During this initial movement all parts of the tool travel together but when the tool reaches the position shown in FIG. 2 the bearing 6 engages bearing 7, thereby stopping thev downward movement of the rotor 2 and shaft 16. Continued downward movement of the actuator 1 causes the spiral teeth 15 on sleeve 11 to slide along the spiral grooves 21 in shaft 16, thereby gradually rotating the shaft to advance the cutting teeth from the In one side of the actuator is a broken-line position to the full-line position in FIG. 4. When the bore B has been recessed to the desired depth, as determined by the adjustment of collar 8 on actuator 1, the collarseats on collar 4 as shown in FIG. 3, thereby stopping the advance of the cutting teeth through the slot 25. During the second stage of the advance, from FIG. 2 to FIG. 3, the springs 22 and 23 are compressed, thereby to return the parts to the position shown in FIG. 1 when the actuator is retracted.

From the foregoing it will be evident that the bits are small and inexpensive and that they may be replaced quickly and easily, merely by removing screws 28 through slot 25. Also it will be evident that the bit -26 is held against chattering and vibration by the bearings 18 and 19 on opposite sides of the cutter and adjacent thereto.

It should be understood that the present disclosure is for the purpose of illustration only andthat this invention includes all modifications and equivalents which fall within the scope of the` appended claims.

I claim:

1. For cutting an annular groove in a bore, a recessing tool comprising a tubular rotor having its forward end small enough to extend into said bore, a shaft journaled in the rotor with its axis offset from the axis of the rotor, an annular slot in said end, a bit mounted on said shaft to project through said slot when the shaft is turned relatively to the rotor, means to turn the shaft as aforesaid while the rotor is rotating, and a bearing for.

said shaft in said end beyond said slot. d

2. A tool according to claim 1 further characterized by means 4accessible through said slot for detachably mounting a bit on said shaft.

3. A tool according to claim 1 wherein the shaft is turned as aforesaid by a sleeve slidable between the lrotor and shaft with a spiral tooth on the sleeve fitting in a spiral groove in the shaft.

4. A tool according to cliam 1 further characterized by a bearing for said lrotor beyond said slot.

No references cited.

WILLIAM W. DYER, IR., Primary Examiner.

GERALD A. DOST, Assistant Examiner. 

1. FOR CUTTING AN ANNULAR GROOVE IN A BORE, A RECESSING TOOL COMPRISING A TUBULAR ROTOR HAVING ITS FORWARD END SMALL ENOUGH TO EXTEND INTO SAID BORE, A SHAFT JOURNALED IN THE ROTOR WITH ITS AXIS OFFSET FORM THE AXIS OF THE ROTOR, AN ANNULAR SLOT IN SAID END, A BIT MOUNTED ON SAID SHAFT TO PROJECT THROUGH SAID SLOW WHEN THE SHAFT IS TURNED RELATIVELY TO THE ROTOR, MEANS TO TURN THE SHAFT AS AFORESAID WHILE THE ROTOR IS ROTATING, AND A BEARING FOR SAID SHAFT IN SAID END BEYOND SAID SLOT. 